posted on Aug, 3 2011 @ 07:32 PM
The difference between starvation and fasting....
Fasting allows for insulin levels to plummet, which in turn allows for fatty acids to move freely in and out of fat cells as other cells need them for
fuel. Unless your hypothalamus is jacked...then fat will used for fuel. Only about 150g of glucose per day is needed (by the brain) but research has
shown that the brain adapts to frequent periods of ketosis by burning ketones when fasting (ketones are the byproduct of fat oxidation). This could
be irrelevant, however, because the body can store up to around 100g of glycogen, which converts to glucose as the body needs it (glyconeogenesis), in
the liver and about 400-500g in the muscles. There are plenty endogenous sources for calories. Where they are coming from will determine if a person
is starving or fasting. (keep in mind, too, that when you fast any longer than 48 hours..your body's metabolism will slow down due to the inactivity
of the digestion system, which is the second most energy-demanding "system" behind the brain.
Starving...well....when liver glycogen is depleted, the body's last reserve of glucose is in the muscles. The only problem is, muscle glycogen can
only be metabolized by muscle; it can't be released into the bloodstream. So...when other cells such as the brain need glucose for fuel, the body
turns to lean tissue for protein to convert to glucose (gluconeogenesis). The first source is the skeletal muscle, since skeletal muscle is the last
on the list of essential organs needed to sustain life. Eventually, other organs with available protein will be atrophied and last will be the heart
(the heart IS a muscle with protein). Then heart failure. And death.
Fasting stops and starving starts when muscle wasting begins.